Back to Search Start Over

The Transpolar Drift as a Source of Riverine and Shelf‐Derived Trace Elements to the Central Arctic Ocean

Authors :
Charette, Matthew A.
Kipp, Lauren E.
Jensen, Laramie T.
Dabrowski, Jessica S.
Whitmore, Laura M.
Fitzsimmons, Jessica N.
Williford, Tatiana
Ulfsbo, Adam
Jones, Elizabeth
Bundy, Randelle M.
Vivancos, Sebastian M.
Pahnke, Katharina
John, Seth G.
Xiang, Yang
Hatta, Mariko
Petrova, Mariia V.
Heimbürger‐Boavida, Lars‐Eric
Bauch, Dorothea
Newton, Robert
Pasqualini, Angelica
Agather, Alison M.
Amon, Rainer M. W.
Anderson, Robert F.
Andersson, Per S.
Benner, Ronald
Bowman, Katlin L.
Edwards, R. Lawrence
Gdaniec, Sandra
Gerringa, Loes J. A.
González, Aridane G.
Granskog, Mats
Haley, Brian
Hammerschmidt, Chad R.
Hansell, Dennis A.
Henderson, Paul B.
Kadko, David C.
Kaiser, Karl
Laan, Patrick
Lam, Phoebe J.
Lamborg, Carl H.
Levier, Martin
Li, Xianglei
Margolin, Andrew R.
Measures, Chris
Middag, Rob
Millero, Frank J.
Moore, Willard S.
Paffrath, Ronja
Planquette, Hélène
Rabe, Benjamin
Reader, Heather
Rember, Robert
Rijkenberg, Micha J. A.
Roy‐Barman, Matthieu
Rutgers van der Loeff, Michiel
Saito, Mak
Schauer, Ursula
Schlosser, Peter
Sherrell, Robert M.
Shiller, Alan M.
Slagter, Hans
Sonke, Jeroen E.
Stedmon, Colin
Woosley, Ryan J.
Valk, Ole
Ooijen, Jan
Zhang, Ruifeng
Source :
Journal of Geophysical Research - Oceans; May 2020, Vol. 125 Issue: 5
Publication Year :
2020

Abstract

A major surface circulation feature of the Arctic Ocean is the Transpolar Drift (TPD), a current that transports river‐influenced shelf water from the Laptev and East Siberian Seas toward the center of the basin and Fram Strait. In 2015, the international GEOTRACES program included a high‐resolution pan‐Arctic survey of carbon, nutrients, and a suite of trace elements and isotopes (TEIs). The cruises bisected the TPD at two locations in the central basin, which were defined by maxima in meteoric water and dissolved organic carbon concentrations that spanned 600 km horizontally and ~25–50 m vertically. Dissolved TEIs such as Fe, Co, Ni, Cu, Hg, Nd, and Th, which are generally particle‐reactive but can be complexed by organic matter, were observed at concentrations much higher than expected for the open ocean setting. Other trace element concentrations such as Al, V, Ga, and Pb were lower than expected due to scavenging over the productive East Siberian and Laptev shelf seas. Using a combination of radionuclide tracers and ice drift modeling, the transport rate for the core of the TPD was estimated at 0.9 ± 0.4 Sv (106m3s−1). This rate was used to derive the mass flux for TEIs that were enriched in the TPD, revealing the importance of lateral transport in supplying materials beneath the ice to the central Arctic Ocean and potentially to the North Atlantic Ocean via Fram Strait. Continued intensification of the Arctic hydrologic cycle and permafrost degradation will likely lead to an increase in the flux of TEIs into the Arctic Ocean. A major feature of the Arctic Ocean circulation is the Transpolar Drift (TPD), a surface current that carries ice and continental shelf‐derived materials from Siberia across the North Pole to the North Atlantic Ocean. In 2015, an international team of oceanographers conducted a survey of trace elements in the Arctic Ocean, traversing the TPD. Near the North Pole, they observed much higher concentrations of trace elements in surface waters than in regions on either side of the current. These trace elements originated from land, and their journey across the Arctic Ocean is made possible by chemical reactions with dissolved organic matter that originates mainly in Arctic rivers. This study reveals the importance of rivers and shelf processes combined with strong ocean currents in supplying trace elements to the central Arctic Ocean and onward to the Atlantic. These trace element inputs are expected to increase as a result of permafrost thawing and increased river runoff in the Arctic, which is warming at a rate much faster than anywhere else on Earth. Since many of the trace elements are essential building blocks for ocean life, these processes could lead to significant changes in the marine ecosystems and fisheries of the Arctic Ocean. The Transpolar Drift is a source of shelf‐ and river‐derived elements to the central Arctic OceanThe TPD is rich in dissolved organic matter (DOM), which facilitates long‐range transport of trace metals that form complexes with DOMMargin trace element fluxes may increase with future Arctic warming due to DOM release from permafrost thaw and increasing river discharge

Details

Language :
English
ISSN :
21699275 and 21699291
Volume :
125
Issue :
5
Database :
Supplemental Index
Journal :
Journal of Geophysical Research - Oceans
Publication Type :
Periodical
Accession number :
ejs53688026
Full Text :
https://doi.org/10.1029/2019JC015920